Prior to the present invention, as is generally well recognized in the railway industry, the throttle controller assemblies which are used in a railway type locomotive are mechanical type throttle controllers. These mechanical type throttle controller assemblies normally utilize a number of mechanical devices in order to accomplish actuation of the necessary microswitches and/or contacts. It is further well known, for example, that cams are used extensively in this application in order to accomplish the required actuation of the various microswitches and/or contacts which are present in the mechanical type throttle controller. Furthermore, it is rather difficult to perform any type of diagnostic tests on these mechanical throttle controllers and such tests which can be performed are accomplished in a more or less manual manner by the operator of such locomotive.
In addition, the mechanical type throttle controllers, presently in use on railway locomotives, have a number of other relatively serious drawbacks and/or limitations. As would be expected, these limitations have become more pronounced as the length of freight trains has grown in modern railroading. One of the primary reasons for this is because the use of more and more locomotives are required in a train consist in order to pull and/or push the added loads being hauled. For example, these mechanical type throttle controllers utilize either microswitches or contacts to control the voltage that is being applied to the trainline. Furthermore, there is no provision in these prior art mechanical throttle controllers for a possible shut down of the system in the event of an output over current.
Additionally, these mechanical type throttle controllers are not equipped to provide the operator of the locomotive with any important feedback information and, consequently, they may not recognize a potential failure situation so that some type of corrective action could be taken. Throttle controllers of the mechanical type also utilize either a resistive type voltage divider or a high power potentiometer in order to control the voltage output and they are not equipped for shutdown or voltage regulation.
The prior art mechanical throttle controllers provide labels over the mechanical handles to convey only the position of the handle to the locomotive operator. However, these mechanical throttle controllers are not equipped to display certain other relevant information such as various diagnostic information, status information and/or warning type messages.
Furthermore, in a situation where it is either desirable or necessary to provide the required throttle control from a remote host over the communication lines, the currently used mechanical type throttle controllers require that a number of additional relays be used.
It can be seen from the above discussion of the mechanical type throttle controller assemblies presently used in the railroad industry that there is an unfilled need which exists in the railroad industry for an improved railway locomotive type throttle controller assembly which will provide both enhanced performance capability, additional functions which are not possible to accomplish with the prior art mechanical type throttle controllers and more consistent reliability.
With the development of the improved electronically controlled railway locomotive throttle controller, for which a patent application is being filed concurrent herewith, as discussed above a need exists for a method of performing reliable diagnostic testing of such improved electronically controlled throttle controller.